JP4106685B2 - Supercritical vapor compression cycle - Google Patents

Supercritical vapor compression cycle Download PDF

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JP4106685B2
JP4106685B2 JP2002268702A JP2002268702A JP4106685B2 JP 4106685 B2 JP4106685 B2 JP 4106685B2 JP 2002268702 A JP2002268702 A JP 2002268702A JP 2002268702 A JP2002268702 A JP 2002268702A JP 4106685 B2 JP4106685 B2 JP 4106685B2
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refrigerant
pressure
adsorber
compressor
supercritical
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JP2004108617A (en
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朝郁 吉川
克己 藤間
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Mayekawa Manufacturing Co
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B9/00—Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point
    • F25B9/002—Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point characterised by the refrigerant
    • F25B9/008—Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point characterised by the refrigerant the refrigerant being carbon dioxide
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2309/00—Gas cycle refrigeration machines
    • F25B2309/06—Compression machines, plants or systems characterised by the refrigerant being carbon dioxide
    • F25B2309/061—Compression machines, plants or systems characterised by the refrigerant being carbon dioxide with cycle highest pressure above the supercritical pressure
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2400/00—General features or devices for refrigeration machines, plants or systems, combined heating and refrigeration systems or heat-pump systems, i.e. not limited to a particular subgroup of F25B
    • F25B2400/13—Economisers
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2400/00—General features or devices for refrigeration machines, plants or systems, combined heating and refrigeration systems or heat-pump systems, i.e. not limited to a particular subgroup of F25B
    • F25B2400/16—Receivers
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2600/00—Control issues
    • F25B2600/05—Refrigerant levels

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Physics & Mathematics (AREA)
  • Mechanical Engineering (AREA)
  • Thermal Sciences (AREA)
  • General Engineering & Computer Science (AREA)
  • Air-Conditioning For Vehicles (AREA)

Description

【０００１】
【発明の属する技術分野】
本発明は、高圧側では凝縮しないＣＯ２等の吸着性のある冷媒を使用する超臨界蒸気圧縮サイクルにおける、能力調整機構、特に高圧側冷媒の吸着により冷媒充填量を加減する吸着調整機能を備えた超臨界蒸気圧縮サイクルに関する。
【０００２】
近年地球環境汚染防止の観点により、特にオゾン層の破壊防止と地球温暖化防止のため、従来から使用されてきたフロンに代わる自然冷媒の一つであり毒性が無く、自然界に多く存在するＣＯ２の使用が見直され、ＣＯ２を冷媒とする蒸気圧縮式冷凍サイクルの使用が暫時拡大の傾向にある。
ところで、ＣＯ２は３１．０６℃の低い温度で臨界点に達するので、これを冷媒とする蒸気圧縮サイクルは前記臨界点を越える臨界域を含むサイクルとなり、また凝縮過程が高温で顕熱変化となり、冷却サイクルには前記顕熱変化に対応するため相変化をする凝縮過程は無く、それとは異なるガス冷却過程を持つ。
【０００３】
【従来の技術】
通常の蒸気圧縮冷凍サイクル装置の冷凍能力制御は蒸発器を通過する冷媒の質量流量の制御により行なわれている。
しかし、超臨界蒸気圧縮サイクルにおいては、圧縮機より下流の膨張弁までは液化されることなく送られ、その間の高サイド（ガスクーラの出口）側には液溜めタンクが設けられず、通常の蒸気圧縮冷凍サイクルに見られる過熱度制御を用いることが出来ないため、何らかの高圧圧力や冷凍能力を制御する機構が必要となっている。
【０００４】
上記した高サイドにおいて超臨界条件下で作動される超臨界蒸気圧縮サイクルにおける冷凍能力の調整手段としては、循環冷媒を調整することにより高サイド圧力を制御する技術が特許文献１に開示されている。
【０００５】
上記文献に開示されているサイクル構成は、図３に示すように、冷媒を超臨界状態に圧縮する圧縮機１０１と、圧縮した冷媒を放熱冷却するガスクーラ１０２と、高圧ラインと低圧ラインを流れる冷媒を熱交換させる内部熱交換器１０３と、冷媒を減圧する膨張弁１０４と、減圧により気液二相混合体になりその液相が蒸発する蒸発器１０５と、蒸発器から流出された冷媒の気液分離を行う気液分離器１０６とより構成する。
なお、前記内部熱交換器１０３の熱交換により、高サイドの冷媒温度は一層下降され冷却能力を向上させるとともに、冷却された冷媒は膨張弁１０４によって減圧され蒸発器１０５で蒸発したのち、気液分離器１０６で気液分離され、その後前記内部熱交換器１０３で高サイドの冷媒と熱交換をしてさらに加熱され、圧縮機１０２へ過熱蒸気となり還流する。
【０００６】
則ち、図４に示すモリエル線図も参照して、圧縮機１０１は点Ａより点Ｂへ温度とともに圧力を上げ、ガスクーラ１０２では冷媒の圧力を維持したまま、点Ｂから点Ｃへ温度を下げる。
若し、ここで点Ｃから膨張弁１０４へ高圧蒸気を送って断熱膨張させると、圧力は下がって点Ｃの真下の点Ｅ’へ移動する。ついで、蒸発器１０５では点Ｅ’から飽和蒸気圧線Ｓとの交点Ｆまでの吸熱が行なわれる。
内部熱交換器１０３は、その高圧側熱交換通路１０３ａを通過する高圧冷媒を点Ｃから点Ｄまで降温させ、点Ｅ’を点Ｅに移動することにより、蒸発器１０５での吸熱量をより多くして冷凍効果を増加させ、効率を向上している。
【０００７】
一方、蒸発器１０５と気液分離器１０６を通過して点Ｆにある冷媒は、内部熱交換器１０３の低圧側熱交換通路１０３ｂを経由し高圧側熱交換通路１０３ａ側への放熱分だけ加熱されて昇温し点Ａに還流する。
ところが、上記低圧側熱交換通路１０３ｂにおける温度上昇Ｆ−Ａにより圧縮機１０１の吐出温度は略それに比例して昇温する。特に熱負荷が大きいと、圧力上昇に伴い吐出温度が上昇し、それに加えて内部熱交換器１０３の熱交換量が増加（Ｃ−Ｄ、Ｆ−Ａ）すると、吐出温度は更に大になる逆効果を持っている。
【０００８】
一般に高サイド（ガスクーラ出口側）の圧力を上げると、冷凍能力は向上するが、圧縮機にかかる動力は大となり、冷凍能力／動力の比である成績係数ＣＯＰと前記ガスクーラ（放熱器）出口圧力との関係は図５に示す線図となりガスクーラ出口圧力の上昇につれＣＯＰも上昇変化するがその変化にはピーク値が存在する。
【０００９】
従って、ガスクーラ出口の温度に応じてガスクーラ出口の圧力を変え、ＣＯＰがピーク値になるように超臨界蒸気圧縮サイクルを運転することが要求される。
【００１０】
そのため、特許文献２に開示された提案では、
圧縮機から吐出された超臨界高圧冷媒と蒸発器で気化した低圧冷媒とを適度に内部熱交換器で熱交換して冷房効率を向上するとともに、過度の熱交換による圧縮機吐出温度の上昇、ガスクーラ出口圧力の上昇を防ぐ超臨界蒸気圧縮サイクルを提供している。
【００１１】
また、特許文献３に開示された提案では、図６に示すように、圧縮機５１と、ガスクーラ５２と、熱交換器５７とポンプ６３と水素取り出し装置５８とそれらを結ぶ往復管路６１、６２とよりなる水素取り出し熱交換部６８と、膨張弁５４と、蒸発器５５と、気液分離器５６とより構成し、
前記熱交換器５７は、前記ガスクーラ５２と膨張弁５４との間を結びガスクーラ５２を経由した圧縮機５１より吐出された超臨界高圧冷媒を第１の熱交換通路５７ａに導入し、第２の熱交換通路５７ｂとの間で熱交換する構成にしてある。
水素取り出し装置５８は、水素吸蔵合金水素取り出し装置で、この装置内には、Ｌａ−Ｎｉ、Ｔｉ−Ｎｉ、Ｍｇ−Ｎｉ、Ｆｅ−Ｔｉ等の水素吸蔵合金５９が充填され、その中に２次冷媒が熱交換を受ける熱交換路６０が配設されている。
上記第２の熱交換通路５７ｂには、水素取り出し装置５８の熱交換路６０から往復管路６１、６２が接続され、水素吸蔵合金の吸蔵反応により冷却された前記２次冷媒（エチレングリコール等の不凍液）が、配管６１に設けられたポンプ６３により導入する構成にしてある。
【００１２】
上記構成よりなる本提案の超臨界蒸気圧縮サイクルは下記に示すように作動する。則ち、圧縮機５１が冷媒を臨界状態に圧縮し、吐出された超臨界高圧冷媒をガスクーラ５２に導入して放熱冷却される。
ガスクーラ５２を通過した超臨界高圧冷媒はを熱交換器５７の第１の熱交換通路５７ａに導入して、第２の熱交換通路５７ｂの２次冷媒と熱交換し、さらに温度を下げ、冷却効率を向上する。
上記第２の熱交換通路５７ｂで熱交換され、温度上昇した２次冷媒は、配管６２を経由し水素取り出し装置５８に戻り熱交換路６０で再び冷却される。
【００１３】
上記提案の場合は、従来の内部熱交換器に代えて、水素吸蔵合金の水素放出時の吸熱反応を利用して超臨界高圧冷媒を冷却するようにしたから、冷却効率が高く、超臨界蒸気圧縮サイクルの効率を向上し、また圧縮機の冷媒吐出温度の過度上昇が抑えられ圧縮機の信頼性を向上する。
【００１４】
上記した従来の提案を見るに、冷却効率の向上には相応の効果が見受けられるが、超臨界蒸気圧縮サイクルの能力調整に際して、高サイドにおける冷媒充填量の加減により行う根本的調整手段は見られない。
【００１５】
【特許文献１】
特公平７−１８６０２号公報
【特許文献２】
特開２００１−２３５２３９公報
【特許文献３】
特開２００１−２３５２４０公報
【００１６】
【発明が解決しようとする課題】
本発明は、上記超臨界蒸気圧縮サイクルにおいて、高サイドでは凝縮しない高圧冷媒に対し、液溜めを設け内部熱交換器を介して行う低圧冷媒の還流による高圧冷媒の冷凍能力調整を行う従来手段とは構想を異にした独自の見地に立って、吸着性のあるＣＯ２等の冷媒に対して冷凍能力制御可能の超臨界蒸気圧縮サイクルの提供を目的とする。
【００１７】
【課題を解決するための手段】
そこで、本発明の超臨界蒸気圧縮サイクルは、ＣＯ２等の吸着性冷媒を超臨界状態に圧縮する圧縮機と、該圧縮機により圧縮された高圧高温冷媒を冷却するガスクーラと、前記冷却された超臨界高圧低温冷媒を減圧する膨張弁と、減圧した気液二相の低圧冷媒が蒸発して冷熱源を形成する蒸発器とよりなる超臨界蒸気圧縮サイクルにおいて、
前記圧縮機とガスクーラとの間に吸着器を設け、該吸着器による冷媒吸着量により高圧側の冷媒充填量を調整するとともに、
前記吸着器は、該吸着器の熱交換回路の二次側を、前記ガスクーラ出口より圧縮機中間ポートへ絞り弁を介しての還流管路に設け、前記絞り弁の絞り度の加減により発生する蒸発温度の変化を前記熱交換回路の一次側に導出させ、吸着器の吸着温度を加減する構成としたことを特徴とする。
【００１８】
上記発明は、超臨界域でサイクルを形成する超臨界蒸気圧縮サイクルを対象とし、吸着性のあるＣＯ２等の冷媒に対して行うもので、サイクル閉鎖系において液溜めを設けることなく、冷媒の吸着性を利用した吸脱着によるサイクル系の高サイドの冷媒充填量を加減して、能力調整を可能としたもので、
圧縮機とガスクーラとの間で冷媒の吸脱着を行う吸着器を設ける構成にしてある。
【００１９】
斯かる本発明の超臨界蒸気圧縮サイクルにおける、
前記吸着器は、吸着温度の加減により吸着量を可変とする構成が好ましく、例えば吸水量の加減により冷媒吸着量を加減する。
【００２１】
上記発明は、吸着器の吸着量を調整する熱交換回路を吸着器内に設け、その二次側を、ガスクーラ出口側より分岐して減圧用の絞り弁を経由して圧縮機のエコノマイザポートを形成する中間ポートに至る管路内に設け、ガスクーラ出口より送出された高圧冷媒を前記絞り弁を介しての減圧蒸発により前記管路内に低温雰囲気を形成させ、該低温雰囲気温度を前記熱交換回路の二次側を経由して一次側回路に導出させ、吸着器温度の低温維持ないし低温の度合いを加減して、吸着器によるＣＯ２冷媒の吸着を行なわせ、高圧側の冷媒充填量を変化させ、負荷に対応する構成にしてある。
【００２２】
【発明の実施の形態】
以下、本発明を図に示した実施例を用いて詳細に説明する。但し、この実施例に記載される構成部品の寸法、材質、形状、その相対配置などは特に特定的記載が無い限り、この発明の範囲をそれのみに限定する趣旨ではなく単なる説明例に過ぎない。
図１は、本発明の実施の前提となる超臨界蒸気圧縮サイクルの一実施例の概略構成を示す図で、図２は図１の別の実施例の概略構成を示す図である。
【００２３】
図１に見るように本発明の実施の前提となる超臨界蒸気圧縮サイクルの概略構成は、冷媒にＣＯ２等の吸着性冷媒を使用して超臨界状態まで加圧する圧縮機１０と、圧縮された高圧冷媒を顕熱冷却するガスクーラ１１と、該クーラにより冷却された超臨界高圧冷媒を減圧する膨張弁１２と、該膨張弁により膨張して減圧され気液二相化した低圧冷媒の液相を蒸発して外部へ冷熱を送出する蒸発器１３と、前記圧縮機１０とガスクーラ１１との間に設けた前記吸着器を形成する冷媒吸着部１４とより構成し、前記冷媒吸着部１４を圧縮機１０とガスクーラ１１との間に介在させ、通過する高圧冷媒の吸着により高圧側の冷媒充填量を変化させ冷凍能力制御を可能としたものである。
【００２４】
上記冷媒吸着部１４は、吸着収納部１４ａと該収納部に充填されたゼオライト等の吸着剤とよりなり、該吸着剤は吸着収納部１４ａを介して圧縮機１０よりガスクーラ１１に通ずる高圧冷媒の管路に介在させ、外部よりの冷熱２０の供給により所要量の冷媒の吸着を行なわせる構成にしてある。
【００２５】
図２には、本発明の実施の前提となる別の実施例の概略構成を示してあるが、本実施例の超臨界蒸気圧縮サイクルは、ＣＯ２等の吸着性冷媒を超臨界状態まで加圧する圧縮機１０と、圧縮された高圧冷媒を顕熱冷却するガスクーラ１１と、該クーラにより冷却された超臨界高圧冷媒を減圧する膨張弁１２と、該膨張弁により膨張して減圧され気液二相化した低圧冷媒の液相を蒸発して外部へ冷熱を送出する蒸発器１３と、前記吸着器を形成する冷媒吸着部２１とより構成し、前記圧縮機１０とガスクーラ１１との間に介在させた吸着収納部１７を通過する高圧冷媒よりＣＯ２冷媒を吸着して高圧側の冷媒充填量を変化させ冷凍能力制御を可能としたものである。
【００２６】
上記冷媒吸着部２１は、前記ガスクーラ１１と圧縮機１０との間を結ぶ高圧冷媒の管路に介在させた吸着収納部１７と、該収納部に充填内蔵されたゼオライト等の吸着剤と、該収納部に設けられた熱交換回路１８と、前記ガスクーラ１１の出口より分岐して絞り弁１６を経由して圧縮機１０の中間ポート１０ａに通ずる帰還管路１９とよりなり、
前記熱交換回路１８は、吸着収納部１７に設けた一次側熱交換回路１８ａと帰還管路１９に設けた二次側熱交換回路１８ｂとよりなり、二次側熱交換回路１８ｂより一次側熱交換回路１８ａへ前記帰還管路１９内に形成された低温雰囲気温度を導出して、吸着収納部１７に内蔵した吸着剤に吸着用冷熱を与え、通過する高圧冷媒より所要のＣＯ２冷媒を吸着させる構成としたもので、前記絞り弁１６の開度により蒸発量を変えて吸着剤の温度を変え吸着量の変化により高圧側冷媒充填量を変化させ負荷に対応する構成にしてある。
【００２７】
なお、ＣＯ２冷媒の吸着の加減は吸着剤周囲への冷熱の供給量を加減し、冷熱の供給を停止することにより雰囲気温度の低下を停止させ、吸着を低減ないし停止する構成にしてある。
【００２８】
上記構成により負荷の変動に対応して高圧側の最適冷媒充填量を設定できるので高効率のサイクル運転を可能にしている。
【００２９】
【発明の効果】
上記構成により、本発明は下記効果を奏する。
本発明は、超臨界蒸気圧縮サイクルにおいて、高サイドでは凝縮しない高圧冷媒に対し、液溜めを設け内部熱交換器を介して行う低圧冷媒の還流による高圧冷媒の冷却を行うことなく可能とした冷凍能力調整手段であって、該手段を形成する冷媒の吸着による高圧側の冷媒充填量を変化させて冷凍能力制御を行うようにしたため、従来例に見られた随伴事項に対するサイクルバランスを考慮に入れた煩雑な処理等は不必要となる。
【図面の簡単な説明】
【図１】 本発明の実施の前提となる超臨界蒸気圧縮サイクルの一実施例の概略構成を示す図である。
【図２】 本発明の実施の前提となる超臨界蒸気圧縮サイクルの別の実施例の概略構成を示す図である。
【図３】 従来の超臨界冷凍サイクルの冷凍能力調整装置の概要構成を示す図である。
【図４】 図３の冷凍サイクルのモリエル線図である。
【図５】 図３における放熱器出口圧力に対する、出口温度を変えた場合のＣＯＰのピーク値の変化状況を示す図である。
【図６】 図３に示す従来例の別の構成の概要を示す図である。[0001]
BACKGROUND OF THE INVENTION
The present invention includes a capacity adjustment mechanism in a supercritical vapor compression cycle that uses an adsorbent refrigerant such as CO 2 that does not condense on the high-pressure side, particularly an adsorption adjustment function that adjusts the refrigerant charge amount by adsorption of the high-pressure side refrigerant. It relates to the supercritical vapor compression cycle.
[0002]
The viewpoint of the recent prevent global environmental pollution, in particular for preventing destruction and global warming prevention of the ozone layer, one a is toxic natural refrigerant in place of CFC have been used conventionally without abundant in nature CO 2 The use of the vapor compression refrigeration cycle using CO 2 as a refrigerant tends to expand for a while.
By the way, since CO 2 reaches a critical point at a low temperature of 31.06 ° C., the vapor compression cycle using this as a refrigerant becomes a cycle including a critical region exceeding the critical point, and the condensation process becomes a sensible heat change at a high temperature. In the cooling cycle, there is no condensation process that undergoes a phase change to cope with the sensible heat change, and a different gas cooling process is provided.
[0003]
[Prior art]
The refrigerating capacity control of a normal vapor compression refrigeration cycle apparatus is performed by controlling the mass flow rate of the refrigerant passing through the evaporator.
However, in the supercritical vapor compression cycle, the expansion valve downstream of the compressor is sent without being liquefied, and a liquid reservoir tank is not provided on the high side (gas cooler outlet) side between them, so that normal steam Since the superheat control found in the compression refrigeration cycle cannot be used, a mechanism for controlling some high pressure and refrigeration capacity is required.
[0004]
As a refrigeration capacity adjusting means in the supercritical vapor compression cycle operated under supercritical conditions on the high side described above, Patent Document 1 discloses a technique for controlling the high side pressure by adjusting the circulating refrigerant. .
[0005]
As shown in FIG. 3, the cycle configuration disclosed in the above document includes a compressor 101 that compresses a refrigerant to a supercritical state, a gas cooler 102 that radiates and cools the compressed refrigerant, and a refrigerant that flows through a high-pressure line and a low-pressure line. An internal heat exchanger 103 for exchanging heat, an expansion valve 104 for depressurizing the refrigerant, an evaporator 105 that becomes a gas-liquid two-phase mixture by depressurization, and its liquid phase evaporates, and the refrigerant gas discharged from the evaporator It comprises a gas-liquid separator 106 that performs liquid separation.
The heat exchange of the internal heat exchanger 103 further lowers the refrigerant temperature on the high side to improve the cooling capacity, and the cooled refrigerant is decompressed by the expansion valve 104 and evaporated by the evaporator 105, and then the gas-liquid Gas-liquid separation is performed by the separator 106, and then heat is exchanged with the high-side refrigerant in the internal heat exchanger 103, which is further heated and recirculates as superheated steam to the compressor 102.
[0006]
That is, referring also to the Mollier diagram shown in FIG. 4, the compressor 101 increases the pressure from the point A to the point B together with the temperature, and the gas cooler 102 increases the temperature from the point B to the point C while maintaining the refrigerant pressure. Lower.
If the high-pressure steam is sent from the point C to the expansion valve 104 to perform adiabatic expansion, the pressure drops and moves to a point E ′ immediately below the point C. Next, the evaporator 105 absorbs heat from the point E ′ to the intersection F with the saturated vapor pressure line S.
The internal heat exchanger 103 lowers the temperature of the high-pressure refrigerant passing through the high-pressure side heat exchange passage 103a from the point C to the point D and moves the point E ′ to the point E, thereby further increasing the heat absorption amount in the evaporator 105. Increasing the freezing effect increases the efficiency.
[0007]
On the other hand, the refrigerant at the point F passing through the evaporator 105 and the gas-liquid separator 106 is heated by the amount of heat released to the high pressure side heat exchange passage 103a side via the low pressure side heat exchange passage 103b of the internal heat exchanger 103. Then, the temperature is raised and refluxed to point A.
However, the discharge temperature of the compressor 101 increases substantially in proportion to the temperature increase F-A in the low-pressure side heat exchange passage 103b. In particular, when the heat load is large, the discharge temperature rises with an increase in pressure. In addition, when the heat exchange amount of the internal heat exchanger 103 increases (CD, FA), the discharge temperature further increases. Have an effect.
[0008]
Generally, when the pressure on the high side (gas cooler outlet side) is increased, the refrigeration capacity improves, but the power applied to the compressor increases, and the coefficient of performance COP, which is the ratio of refrigeration capacity / power, and the gas cooler (radiator) outlet pressure 5 is a diagram shown in FIG. 5, and as the gas cooler outlet pressure rises, the COP also rises, but there is a peak value in the change.
[0009]
Therefore, it is required to operate the supercritical vapor compression cycle so that the COP has a peak value by changing the pressure at the gas cooler outlet according to the temperature at the gas cooler outlet.
[0010]
Therefore, in the proposal disclosed in Patent Document 2,
The supercritical high-pressure refrigerant discharged from the compressor and the low-pressure refrigerant vaporized by the evaporator are appropriately heat-exchanged by the internal heat exchanger to improve the cooling efficiency, and the compressor discharge temperature rises due to excessive heat exchange, A supercritical vapor compression cycle is provided to prevent an increase in gas cooler outlet pressure.
[0011]
Further, in the proposal disclosed in Patent Document 3, as shown in FIG. 6, a compressor 51, a gas cooler 52, a heat exchanger 57, a pump 63, a hydrogen extraction device 58, and reciprocating pipe lines 61 and 62 connecting them. A hydrogen extraction heat exchanging portion 68, an expansion valve 54, an evaporator 55, and a gas-liquid separator 56,
The heat exchanger 57 connects the gas cooler 52 and the expansion valve 54 and introduces the supercritical high-pressure refrigerant discharged from the compressor 51 via the gas cooler 52 into the first heat exchange passage 57a. The heat exchange path 57b is configured to exchange heat.
The hydrogen extraction device 58 is a hydrogen storage alloy hydrogen extraction device, which is filled with a hydrogen storage alloy 59 such as La—Ni, Ti—Ni, Mg—Ni, Fe—Ti, etc. A heat exchange path 60 through which the refrigerant exchanges heat is disposed.
The second heat exchange passage 57b is connected to reciprocating pipes 61 and 62 from the heat exchange path 60 of the hydrogen extraction device 58, and the secondary refrigerant (such as ethylene glycol) cooled by the storage reaction of the hydrogen storage alloy. The antifreeze liquid) is introduced by a pump 63 provided in the pipe 61.
[0012]
The proposed supercritical vapor compression cycle constructed as described above operates as shown below. In other words, the compressor 51 compresses the refrigerant to a critical state, and the discharged supercritical high-pressure refrigerant is introduced into the gas cooler 52 to be cooled by heat radiation.
The supercritical high-pressure refrigerant that has passed through the gas cooler 52 is introduced into the first heat exchange passage 57a of the heat exchanger 57, exchanges heat with the secondary refrigerant in the second heat exchange passage 57b, further reduces the temperature, and cools. Increase efficiency.
The secondary refrigerant that has been heat-exchanged in the second heat-exchange passage 57b and has risen in temperature returns to the hydrogen extraction device 58 via the pipe 62 and is cooled again in the heat-exchange passage 60.
[0013]
In the case of the above proposal, instead of the conventional internal heat exchanger, the supercritical high-pressure refrigerant is cooled by utilizing the endothermic reaction at the time of hydrogen release of the hydrogen storage alloy. The efficiency of the compression cycle is improved, and an excessive increase in the refrigerant discharge temperature of the compressor is suppressed, improving the reliability of the compressor.
[0014]
As seen from the above-mentioned conventional proposals, there is a corresponding effect in improving the cooling efficiency. However, when adjusting the capacity of the supercritical vapor compression cycle, there is no fundamental adjustment means by adjusting the refrigerant charge amount on the high side. Absent.
[0015]
[Patent Document 1]
Japanese Patent Publication No. 7-18602 [Patent Document 2]
JP 2001-235239 A [Patent Document 3]
[Patent Document 1] Japanese Patent Laid-Open No. 2001-235240
[Problems to be solved by the invention]
The present invention provides a conventional means for adjusting the refrigerating capacity of the high-pressure refrigerant by recirculation of the low-pressure refrigerant through a built-in heat exchanger for the high-pressure refrigerant that does not condense on the high side in the supercritical vapor compression cycle. Is intended to provide a supercritical vapor compression cycle capable of controlling the refrigerating capacity of an adsorbent refrigerant such as CO 2 from an original viewpoint with a different concept.
[0017]
[Means for Solving the Problems]
Therefore, the supercritical vapor compression cycle of the present invention includes a compressor that compresses an adsorbent refrigerant such as CO 2 into a supercritical state, a gas cooler that cools a high-pressure high-temperature refrigerant compressed by the compressor, and the cooled In a supercritical vapor compression cycle comprising an expansion valve that depressurizes supercritical high-pressure low-temperature refrigerant and an evaporator that forms a cold heat source by evaporating the decompressed gas-liquid two-phase low-pressure refrigerant,
An adsorber is provided between the compressor and the gas cooler, and the refrigerant charge amount on the high pressure side is adjusted by the refrigerant adsorption amount by the adsorber ,
The adsorber is provided by providing a secondary side of the heat exchange circuit of the adsorber in a reflux pipe line from the gas cooler outlet to a compressor intermediate port via a throttle valve, and is generated by adjusting the throttle degree of the throttle valve. It is characterized in that a change in the evaporation temperature is derived to the primary side of the heat exchange circuit and the adsorption temperature of the adsorber is adjusted.
[0018]
The above invention is directed to a supercritical vapor compression cycle in which a cycle is formed in the supercritical region, and is performed on an adsorbent refrigerant such as CO 2 . The ability to adjust the capacity by adjusting the amount of refrigerant on the high side of the cycle system by adsorption / desorption using adsorptive,
An adsorber that adsorbs and desorbs the refrigerant between the compressor and the gas cooler is provided.
[0019]
In the supercritical vapor compression cycle of the present invention,
The adsorber is preferably configured such that the adsorption amount is variable by adjusting the adsorption temperature. For example, the refrigerant adsorption amount is adjusted by adjusting the water absorption amount.
[0021]
In the above invention, a heat exchange circuit for adjusting the adsorption amount of the adsorber is provided in the adsorber, and its secondary side is branched from the gas cooler outlet side, and the compressor economizer port is connected via a pressure reducing throttle valve. A high-pressure refrigerant provided from the gas cooler outlet is formed in a pipe line leading to the intermediate port to be formed, and a low-temperature atmosphere is formed in the pipe line by decompression evaporation through the throttle valve, and the low-temperature atmosphere temperature is exchanged with the heat. It is led to the primary circuit via the secondary side of the circuit, the adsorber temperature is maintained at a low temperature or the degree of the low temperature is adjusted, and the adsorber is used to adsorb the CO 2 refrigerant. The configuration is changed to correspond to the load.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the embodiments shown in the drawings. However, as long as there is no specific description, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are merely illustrative examples and not intended to limit the scope of the present invention. .
FIG. 1 is a diagram showing a schematic configuration of an embodiment of a supercritical vapor compression cycle which is a premise for carrying out the present invention, and FIG. 2 is a diagram showing a schematic configuration of another embodiment of FIG.
[0023]
As shown in FIG. 1, the schematic configuration of the supercritical vapor compression cycle , which is a premise for carrying out the present invention, includes a compressor 10 that pressurizes the refrigerant to a supercritical state using an adsorbent refrigerant such as CO 2, and the like. A gas cooler 11 that sensiblely cools the high-pressure refrigerant, an expansion valve 12 that depressurizes the supercritical high-pressure refrigerant cooled by the cooler, and a liquid phase of the low-pressure refrigerant that is expanded by the expansion valve and depressurized to be gas-liquid two-phase. And the refrigerant adsorbing part 14 forming the adsorber provided between the compressor 10 and the gas cooler 11 and compressing the refrigerant adsorbing part 14. The refrigerant is interposed between the machine 10 and the gas cooler 11, and the refrigerant charging amount on the high-pressure side is changed by the adsorption of the high-pressure refrigerant passing therethrough, thereby making it possible to control the refrigerating capacity.
[0024]
The refrigerant adsorbing unit 14 includes an adsorbing and storing unit 14a and an adsorbent such as zeolite filled in the storing unit, and the adsorbing agent is a high-pressure refrigerant that communicates from the compressor 10 to the gas cooler 11 through the adsorbing and storing unit 14a. It is configured such that a required amount of refrigerant is adsorbed by supply of cold heat 20 from the outside through a pipe.
[0025]
FIG. 2 shows a schematic configuration of another embodiment as a premise for carrying out the present invention. In the supercritical vapor compression cycle of this embodiment, an adsorptive refrigerant such as CO 2 is added to a supercritical state. A compressor 10 for compressing, a gas cooler 11 for sensible cooling of the compressed high-pressure refrigerant, an expansion valve 12 for decompressing the supercritical high-pressure refrigerant cooled by the cooler, and a gas-liquid two that is expanded and decompressed by the expansion valve. It comprises an evaporator 13 that evaporates the liquid phase of the phased low-pressure refrigerant and sends cold heat to the outside, and a refrigerant adsorbing portion 21 that forms the adsorber, and is interposed between the compressor 10 and the gas cooler 11. The CO 2 refrigerant is adsorbed from the high-pressure refrigerant passing through the adsorbed storage part 17 and the refrigerant charging amount on the high-pressure side is changed to enable the refrigeration capacity control.
[0026]
The refrigerant adsorption unit 21 includes an adsorption storage unit 17 interposed in a high-pressure refrigerant pipe connecting the gas cooler 11 and the compressor 10, an adsorbent such as zeolite filled in the storage unit, A heat exchange circuit 18 provided in the storage unit, and a return pipe 19 branched from the outlet of the gas cooler 11 and leading to the intermediate port 10a of the compressor 10 via the throttle valve 16;
The heat exchange circuit 18 includes a primary side heat exchange circuit 18a provided in the adsorption storage unit 17 and a secondary side heat exchange circuit 18b provided in the return pipe 19, and the primary side heat exchange from the secondary side heat exchange circuit 18b. The low-temperature ambient temperature formed in the return line 19 is derived to the exchange circuit 18a, the adsorbent contained in the adsorption storage unit 17 is given cold for adsorption, and the required CO 2 refrigerant is adsorbed from the high-pressure refrigerant passing therethrough. In this configuration, the evaporation amount is changed depending on the opening degree of the throttle valve 16, the temperature of the adsorbent is changed, and the high-pressure side refrigerant charging amount is changed according to the change in the adsorption amount so as to correspond to the load.
[0027]
In addition, the adjustment of the adsorption of the CO 2 refrigerant is configured to increase or decrease the supply amount of the cold heat around the adsorbent, stop the supply of the cold heat, thereby stopping the decrease in the ambient temperature, and reduce or stop the adsorption.
[0028]
With the above configuration, the optimum refrigerant charging amount on the high-pressure side can be set in response to load fluctuations, so that highly efficient cycle operation is possible.
[0029]
【The invention's effect】
With the above configuration, the present invention has the following effects.
In the supercritical vapor compression cycle, the present invention enables refrigeration that enables high-pressure refrigerant that does not condense on the high side without cooling the high-pressure refrigerant by recirculation of the low-pressure refrigerant that is provided through the internal heat exchanger with a liquid reservoir. The capacity adjustment means is configured to control the refrigerating capacity by changing the refrigerant charging amount on the high pressure side by the adsorption of the refrigerant forming the means, so that the cycle balance with respect to the accompanying items found in the conventional example is taken into consideration. Such complicated processing is unnecessary.
[Brief description of the drawings]
FIG. 1 is a diagram showing a schematic configuration of an embodiment of a supercritical vapor compression cycle which is a premise for carrying out the present invention.
FIG. 2 is a diagram showing a schematic configuration of another embodiment of a supercritical vapor compression cycle which is a premise for carrying out the present invention .
FIG. 3 is a diagram showing a schematic configuration of a conventional refrigeration capacity adjusting device for a supercritical refrigeration cycle.
4 is a Mollier diagram of the refrigeration cycle of FIG. 3. FIG.
FIG. 5 is a diagram showing a change state of a COP peak value when the outlet temperature is changed with respect to the radiator outlet pressure in FIG. 3;
6 is a diagram showing an outline of another configuration of the conventional example shown in FIG. 3; FIG.

Claims (2)

ＣＯ２等の吸着性冷媒を超臨界状態に圧縮する圧縮機と、該圧縮機により圧縮された高圧高温冷媒を冷却するガスクーラと、前記冷却された超臨界高圧低温冷媒を減圧する膨張弁と、減圧した気液二相の低圧冷媒が蒸発して冷熱源を形成する蒸発器とよりなる超臨界蒸気圧縮サイクルにおいて、
前記圧縮機とガスクーラとの間に吸着器を設け、該吸着器による冷媒吸着量により高圧側の冷媒充填量を調整するとともに、
前記吸着器は、該吸着器の熱交換回路の二次側を、前記ガスクーラ出口より圧縮機中間ポートへ絞り弁を介しての還流管路に設け、前記絞り弁の絞り度の加減により発生する蒸発温度の変化を前記熱交換回路の一次側に導出させ、吸着器の吸着温度を加減する構成としたことを特徴とする超臨界蒸気圧縮サイクル。A compressor that compresses an adsorptive refrigerant such as CO 2 to a supercritical state, a gas cooler that cools the high-pressure and high-temperature refrigerant compressed by the compressor, and an expansion valve that decompresses the cooled supercritical high-pressure and low-temperature refrigerant; In a supercritical vapor compression cycle consisting of an evaporator in which a decompressed gas-liquid two-phase low-pressure refrigerant evaporates to form a cold heat source,
An adsorber is provided between the compressor and the gas cooler, and the refrigerant charge amount on the high pressure side is adjusted by the refrigerant adsorption amount by the adsorber ,
The adsorber is provided by providing a secondary side of the heat exchange circuit of the adsorber in a reflux pipe line from the gas cooler outlet to a compressor intermediate port via a throttle valve, and is generated by adjusting the throttle degree of the throttle valve. A supercritical vapor compression cycle characterized in that a change in evaporation temperature is derived to the primary side of the heat exchange circuit, and the adsorption temperature of the adsorber is adjusted . 前記吸着器は、吸着温度の加減により吸着量を可変としたことを特徴とする請求項１記載の超臨界蒸気圧縮サイクル。  The supercritical vapor compression cycle according to claim 1, wherein the adsorption amount of the adsorber is variable by adjusting the adsorption temperature.
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Cited By (2)

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US9194615B2 (en) 2013-04-05 2015-11-24 Marc-Andre Lesmerises CO2 cooling system and method for operating same
US11656005B2 (en) 2015-04-29 2023-05-23 Gestion Marc-André Lesmerises Inc. CO2 cooling system and method for operating same

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* Cited by examiner, † Cited by third party
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US8141381B2 (en) 2006-03-27 2012-03-27 Mayekawa Mfg. Co., Ltd. Vapor compression refrigerating cycle, control method thereof, and refrigerating apparatus to which the cycle and the control method are applied

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9194615B2 (en) 2013-04-05 2015-11-24 Marc-Andre Lesmerises CO2 cooling system and method for operating same
US11656005B2 (en) 2015-04-29 2023-05-23 Gestion Marc-André Lesmerises Inc. CO2 cooling system and method for operating same

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